can Quarto (1.9) support accessible math in pdf via MathML?

[paciorek]

Description

From the documentation, I know that you've added support for ua-2 accessibility (thanks!). When I use this, my pdf passes Ally checking in terms of tagging (in my university's Canvas Ally checking tool). However the Ally check flags that equations are images that are not accessible.

From this LaTeX documentation, it appears that what is needed in the generated .tex file is:

\DocumentMetadata{uncompress,lang=en,
 tagging=on,
 tagging-setup={math/setup=mathml-SE},
 pdfstandard=ua-2,pdfstandard=a-4f}

\documentclass{article}
\usepackage{unicode-math}

Does Quarto 1.9 support accessibility for equations? If not, are there plans to support this?

Additional comments:

1. In testing my own .tex files, I have found that one also needs this in the LaTeX preamble:

   \tagpdfsetup{math/alt/use}
   

2. In testing my own .tex files, it doesn't seem like tagging-setup={math/setup=mathml-SE} is actually needed to generate accessible PDF, including accessible equations.

[mcanouil]

See the issues and 1.9 changelog.

[paciorek]

I don't see that the issues or changelog address equations and my pdfs created with Quarto 1.9.23 are being flagged as having equation images that are not accessible. Can you point specifically to relevant issues or changes?

[mcanouil]

Look at the accessibility issues:

• https://github.com/quarto-dev/quarto-cli/issues?q=is%3Aissue%20state%3Aopen%20label%3Aaccessibility

See also the test PR:

• experiment: enable QUARTO_PDF_STANDARD and run latex/typst tests #14097

[mcanouil]

@paciorek Don't scatter the discussion please. I mentioned the issues and the PRs to show you it was a work in progress with already some great progress in 1.9 (HTML, Typst).

I believe that a number of US public universities have the Ally checking in their LMS in order to comply with the US ADA 2026-04-24 deadline.

Also, this does not help move things forward in any way. Please refrain to make pressure statement like that. Instead, ask or try to figure out how you could help.

Even if not practical, you can always set format: latex and do the final accessibility edition manually. You could also create your own LaTeX template.

[paciorek]

My comments with details of what I was seeing (and precisely what might need to be inserted into the .tex) were meant to be helpful and provide hopefully useful context (not pressure), particularly given I didn't see specific discussion around the question of equations. Putting those details with the PR seemed to be the right place from my outside perspective given you had pointed me there. I'm sorry if you don't see that to be the case, but I would hope the dev team would encourage input even if it doesn't arrive in exactly the format you would like.

None of this discussion takes away from all the great work you all are doing - and thank you.

[mcanouil]

The PR as titled is an experiment to check the current state of the formats with respect to the changes made (mostly on Typst and HTML).
The PR also shows that the formats are checked against several standard, so tracking each warnings in separate issues is not realistic.
Accessibility is one of the biggest concern of the Quarto team and they are working on it.

What you can do right now, is to actually test the LaTeX code you are suggesting using the tools at your disposal (partials, templates, include-in-* options) to see if this actually works.
This would help, but that will likely be for 1.10.
Note also that the templates originally come from Pandoc, with some changes for some formats.

Se for example the issue that seems to track the LaTeX issue for accessibility:

• Accessibility mode for LaTeX jgm/pandoc#5409

[gordonwoodhull]

Hmm, we are using veraPDF for validation and this test case passes:

---
title: "UA math without alt text"
lang: en
format:
  pdf:
    pdf-standard: ua-2
    keep-tex: true
  typst:
    pdf-standard: ua-1
    keep-typ: true
_quarto:
  tests:
    pdf:
      # LaTeX with tagging=on + unicode-math auto-generates MathML for accessibility
      noErrors: default
    typst:
      # Typst requires explicit alt text for math in PDF/UA-1
      shouldError: default
      printsMessage:
        level: ERROR
        regex: "missing alt text"
---

# Math Without Alt Text in PDF/UA

PDF/UA requires alternative text for Formula elements.

- **LaTeX**: Auto-generates MathML via `tagging=on` + `unicode-math` (LuaLaTeX)
- **Typst**: Requires explicit alt text - errors at compile time

Note: PR #13872 adds `alt` attribute support for equations in Quarto.

## Inline Math

The equation $E = mc^2$ is inline.

## Display Math

$$
\int_0^\infty e^{-x^2} dx = \frac{\sqrt{\pi}}{2}
$$

Does the resulting PDF pass Canvas Ally?

[paciorek]

1. I generated a pdf using Quarto 1.9.23 on MacOS via lualatex (quarto render file.qmd --to pdf).

• quarto render reports that it passes the verapdf check.
• It does not pass Canvas Ally. Ally points out that both the inline and non-inline equation images have no alt text.

2. If I do quarto render file.qmd --to typst, typst reports that images and equations should have alt text, as expected.

[gordonwoodhull]

I've independently verified this test using Claude and pikepdf. The PDF has two /Formula structure elements, each with:

• An /AF (Associated File) array containing MathML as application/mathml+xml with /AFRelationship /Supplement — this is the correct UA-2 mechanism
• The actual MathML content is well-formed (e.g., <math xmlns="http://www.w3.org/1998/Math/MathML"> <mi>𝐸</mi> <mo>=</mo> <mi>𝑚</mi> <msup> <mi>𝑐</mi> <mn>2</mn> </msup> </math>)
• TeX source is also attached as a second AF with /AFRelationship /Source

However, there is no /Alt or /ActualText on the Formula elements. This is by design — UA-2 uses the embedded MathML AF as the accessible representation instead of alt text.

So this looks like Canvas Ally is applying UA-1 rules (which require /Alt on Formula elements) rather than recognizing the UA-2 MathML associated file mechanism. The PDF is valid UA-2, but Ally doesn't understand that yet.

There is currently no way to specify alt text for inline equations in Quarto. For cross-referenced block equations you can use

$$
\int_0^\infty e^{-x^2} dx = \frac{\sqrt{\pi}}{2}
$$ {#eq-gaussian-integral alt="The integral of e to the negative x squared from 0 to infinity equals the square root of pi over 2"}

[mcanouil]

I'm not sure alt-text works for LaTeX.
I've added support for this in Typst but didn't know what was expected in LaTeX.

[paciorek]

(in response to @gordonwoodhull 's summary) Ok, thanks! Hopefully Ally will catch up soon.